Industrial cookers and chillers are known in the art which pass food products therethrough on a continuously running conveyor belt. Also sanitizing equipment and features are commonly used whenever food is processed. Cooking techniques which help preserve product characteristics are also known.
Examples of typical prior art techniques are as follows:
Conveyor type freezing and broiling apparatus in stainless steel cabinets with access doors permitting internal manual cleaning has been marketed by Certified Manufacturing, Inc. of Lynwood, Calif. 90262.
Spiral type conveyor paths in a freezing unit circulating cold dry air about a product and having associated belt sanitation equipment is disclosed in U.S. Pat. No. 3,412,476--S. Astrom--Nov. 26, 1968.
Certain techniques resolving deficiencies in cooking and cooling food products are known in batch type food processing equipment where batches are placed in an oven or freezer as long as necessary for processing. Thus, U.S. Pat. No. 3,597,228--M. R. Jeppson--Aug. 3, 1971 introduces steam into a microwave oven to reduce loss of water from the product and cooks in a hot oil bath to brown the product.
Similarly, U.S. Pat. No. 2,846,318--E. J. Kelley et al.--Aug. 5, 1958 introduces humidity in a low pressure freezing gas atmosphere to reduce dehumidification.
However, many unresolved problems remain in the prior art food processing systems, particularly where large volumes of food are rapidly processed on a continuously running conveyor passing through cooking and chilling units.
One order of problems relates to energy efficiency. In many cooking systems hot gases escape, radiation losses are large, particularly where large heated surface areas exist. In both cooking and heating systems there is generally an inefficiency in heat interface surfaces between the heating medium and the food product, requiring a significant expenditure of energy without achieving the end result intended. Particularly there is a lack of acceptable solutions available to the energy losses generally caused by the entrance and exit of conveyor belt from the cooking and chilling units.
Another order of problems relates to food appearance, taste and texture. It is difficult to avoid losses of moisture and food essences in the drying atmosphere of heating ovens and chillers, which both by nature tend to dehydrate a product. Thus, a meat, fish or poultry product in particular will tend to change shape and appearance as well as to lose flavor and moisture in both cooking and cooling processes. Complete uniform cooking throughout without unwanted change to the food texture has been difficult to attain particularly when rapid processing is required in industrial type food processors.
Yet another set of problems comes with the requirement to process food in a sanitary and sanitizable environment. In most systems a disproportionate time span and inefficiency of energy is spent in tearing down a production line for sanitization. Cooking in particular tends to burn on, dry out and accumulate drippings, proteins and other food contamination resulting in unsightly and unsanitary equipment. Also complex equipment has surfaces and interfaces difficult to reach and in warm or protected places where bacteria can breed.
Accordingly, it is an object of this invention to provide improved food processing equipment resolving the foregoing deficiencies of the prior art.